1. Field of the Invention
The present invention relates to an apparatus for forming a liquid crystal fence, and more particularly to an apparatus for forming a liquid crystal fence disposed between a TFT (Thin Film Transistor) substrate and a color filter substrate so as to provide a space for receiving liquid crystal and to couple the TFT substrate to the color filter substrate.
2. Description of the Related Art
In an LCD (Liquid Crystal Display) panel, liquid crystal is interposed between a TFT substrate and a color filter substrate manufactured through fabricating processes different from each other.
An alignment of the liquid crystal is changed corresponding to an electric field formed between the TFT and color filter substrates in response to an external power voltage, so the liquid crystal changes a transmittance of a light provided from an external environment.
The TFT substrate and color filter substrate are separated from each other with a predetermined distance (hereinafter, referred to as a cell gap) so as to provide a space for receiving the liquid crystal therebetween. The cell gap between the TFT substrate and the color filter substrate depends on inherent properties of the liquid crystal. For example, if an LCD panel has a liquid crystal of a TN (Twisted Nematic) mode, the cell gap is about 4.6 □.
In order to supply a liquid crystal to the cell gap between the TFT and color filter substrates, a method that supplies the liquid crystal in a vacuum state (referred to as a vacuum method) or a method that supplies the liquid crystal in a lower-pressure state than an atmospheric pressure (referred to as a dropping method) are generally used.
In the vacuum method, the LCD panel having the cell gap is dipped into a barrel in which the liquid crystal is received. When an inside of the cell gap is changed into the vacuum state, the liquid crystal is sucked up from the barrel into the cell gap due to a pressure difference between the inside of the cell gap and the barrel in which the liquid crystal is received. Thus, the inside of the cell gap may be filled up with the liquid crystal without a void.
However, in the vacuum method, the liquid crystal may be supplied to the inside of the cell gap much greater than a required amount of the liquid crystal. As a result, a pressing process is needed to drain the liquid crystal supplied to the inside of the cell gap after the liquid crystal is supplied to the cell gap. Also, processes, for example, such as a sealing process for sealing an inlet through which the liquid crystal is supplied and a cleaning process for cleaning the LCD panel stained with the liquid crystal while the liquid crystal is supplied, are separately needed.
In the dropping method, one of the TFT substrate and the color filter substrate is provided with a sealant that comprises an ultraviolet-curable material so as to define a liquid crystal receiving area. The liquid crystal is supplied to the liquid crystal receiving area defined by the sealant. The TFT substrate is assembled with the color filter substrate in the lower-pressure state than the atmospheric pressure after the liquid crystal is supplied to the liquid crystal receiving area. When the TFT substrate assembled with the color filter substrate is exposed to the atmospheric pressure, the liquid crystal disposed between the TFT and color filter substrates is uniformly diffused inside the liquid crystal receiving area due to the difference between the pressure of the liquid crystal receiving area of the LCD panel and the atmospheric pressure. Then, the sealant is cured by an exposure to ultraviolet rays.
However, the ultraviolet rays for curing the sealant is irradiated onto the TFT and color filter substrates and the liquid crystal with the sealant. As a result, an alignment layer of the TFT substrate may be damaged and the liquid crystal may be deteriorated.